from langchain_core.messages import MessageLikeRepresentation, AIMessage


def is_token_limit_exceeded(exception: Exception, model_name: str = None) -> bool:
    """Determine if an exception indicates a token/context limit was exceeded.

    Args:
        exception: The exception to analyze
        model_name: Optional model name to optimize provider detection

    Returns:
        True if the exception indicates a token limit was exceeded, False otherwise
    """
    error_str = str(exception).lower()

    # Step 1: Determine provider from model name if available
    provider = None
    if model_name:
        model_str = str(model_name).lower()
        if model_str.startswith('openai:'):
            provider = 'openai'
        elif model_str.startswith('anthropic:'):
            provider = 'anthropic'
        elif model_str.startswith('gemini:') or model_str.startswith('google:'):
            provider = 'gemini'

    # Step 2: Check provider-specific token limit patterns
    if provider == 'openai':
        return _check_openai_token_limit(exception, error_str)
    elif provider == 'anthropic':
        return _check_anthropic_token_limit(exception, error_str)
    elif provider == 'gemini':
        return _check_gemini_token_limit(exception, error_str)

    # Step 3: If provider unknown, check all providers
    return (
            _check_openai_token_limit(exception, error_str) or
            _check_anthropic_token_limit(exception, error_str) or
            _check_gemini_token_limit(exception, error_str)
    )


def _check_openai_token_limit(exception: Exception, error_str: str) -> bool:
    """Check if exception indicates OpenAI token limit exceeded."""
    # Analyze exception metadata
    exception_type = str(type(exception))
    class_name = exception.__class__.__name__
    module_name = getattr(exception.__class__, '__module__', '')

    # Check if this is an OpenAI exception
    is_openai_exception = (
            'openai' in exception_type.lower() or
            'openai' in module_name.lower()
    )

    # Check for typical OpenAI token limit error types
    is_request_error = class_name in ['BadRequestError', 'InvalidRequestError']

    if is_openai_exception and is_request_error:
        # Look for token-related keywords in error message
        token_keywords = ['token', 'context', 'length', 'maximum context', 'reduce']
        if any(keyword in error_str for keyword in token_keywords):
            return True

    # Check for specific OpenAI error codes
    if hasattr(exception, 'code') and hasattr(exception, 'type'):
        error_code = getattr(exception, 'code', '')
        error_type = getattr(exception, 'type', '')

        if (error_code == 'context_length_exceeded' or
                error_type == 'invalid_request_error'):
            return True

    return False


def _check_anthropic_token_limit(exception: Exception, error_str: str) -> bool:
    """Check if exception indicates Anthropic token limit exceeded."""
    # Analyze exception metadata
    exception_type = str(type(exception))
    class_name = exception.__class__.__name__
    module_name = getattr(exception.__class__, '__module__', '')

    # Check if this is an Anthropic exception
    is_anthropic_exception = (
            'anthropic' in exception_type.lower() or
            'anthropic' in module_name.lower()
    )

    # Check for Anthropic-specific error patterns
    is_bad_request = class_name == 'BadRequestError'

    if is_anthropic_exception and is_bad_request:
        # Anthropic uses specific error messages for token limits
        if 'prompt is too long' in error_str:
            return True

    return False


def _check_gemini_token_limit(exception: Exception, error_str: str) -> bool:
    """Check if exception indicates Google/Gemini token limit exceeded."""
    # Analyze exception metadata
    exception_type = str(type(exception))
    class_name = exception.__class__.__name__
    module_name = getattr(exception.__class__, '__module__', '')

    # Check if this is a Google/Gemini exception
    is_google_exception = (
            'google' in exception_type.lower() or
            'google' in module_name.lower()
    )

    # Check for Google-specific resource exhaustion errors
    is_resource_exhausted = class_name in [
        'ResourceExhausted',
        'GoogleGenerativeAIFetchError'
    ]

    if is_google_exception and is_resource_exhausted:
        return True

    # Check for specific Google API resource exhaustion patterns
    if 'google.api_core.exceptions.resourceexhausted' in exception_type.lower():
        return True

    return False


# NOTE: This may be out of date or not applicable to your models. Please update this as needed.
MODEL_TOKEN_LIMITS = {
    "openai:gpt-4.1-mini": 1047576,
    "openai:gpt-4.1-nano": 1047576,
    "openai:gpt-4.1": 1047576,
    "openai:gpt-4o-mini": 128000,
    "openai:gpt-4o": 128000,
    "openai:o4-mini": 200000,
    "openai:o3-mini": 200000,
    "openai:o3": 200000,
    "openai:o3-pro": 200000,
    "openai:o1": 200000,
    "openai:o1-pro": 200000,
    "anthropic:claude-opus-4": 200000,
    "anthropic:claude-sonnet-4": 200000,
    "anthropic:claude-3-7-sonnet": 200000,
    "anthropic:claude-3-5-sonnet": 200000,
    "anthropic:claude-3-5-haiku": 200000,
    "google:gemini-1.5-pro": 2097152,
    "google:gemini-1.5-flash": 1048576,
    "google:gemini-pro": 32768,
    "cohere:command-r-plus": 128000,
    "cohere:command-r": 128000,
    "cohere:command-light": 4096,
    "cohere:command": 4096,
    "mistral:mistral-large": 32768,
    "mistral:mistral-medium": 32768,
    "mistral:mistral-small": 32768,
    "mistral:mistral-7b-instruct": 32768,
    "ollama:codellama": 16384,
    "ollama:llama2:70b": 4096,
    "ollama:llama2:13b": 4096,
    "ollama:llama2": 4096,
    "ollama:mistral": 32768,
    "bedrock:us.amazon.nova-premier-v1:0": 1000000,
    "bedrock:us.amazon.nova-pro-v1:0": 300000,
    "bedrock:us.amazon.nova-lite-v1:0": 300000,
    "bedrock:us.amazon.nova-micro-v1:0": 128000,
    "bedrock:us.anthropic.claude-3-7-sonnet-20250219-v1:0": 200000,
    "bedrock:us.anthropic.claude-sonnet-4-20250514-v1:0": 200000,
    "bedrock:us.anthropic.claude-opus-4-20250514-v1:0": 200000,
    "anthropic.claude-opus-4-1-20250805-v1:0": 200000,
}


def get_model_token_limit(model_string):
    """Look up the token limit for a specific model.

    Args:
        model_string: The model identifier string to look up

    Returns:
        Token limit as integer if found, None if model not in lookup table
    """
    # Search through known model token limits
    for model_key, token_limit in MODEL_TOKEN_LIMITS.items():
        if model_key in model_string:
            return token_limit

    # Model not found in lookup table
    return None


def remove_up_to_last_ai_message(messages: list[MessageLikeRepresentation]) -> list[MessageLikeRepresentation]:
    """Truncate message history by removing up to the last AI message.

    This is useful for handling token limit exceeded errors by removing recent context.

    Args:
        messages: List of message objects to truncate

    Returns:
        Truncated message list up to (but not including) the last AI message
    """
    # Search backwards through messages to find the last AI message
    for i in range(len(messages) - 1, -1, -1):
        if isinstance(messages[i], AIMessage):
            # Return everything up to (but not including) the last AI message
            return messages[:i]

    # No AI messages found, return original list
    return messages
    